Your light looks pretty good actually. I remember some photos of lights that I posted a long time ago and they looked fine in person, but on a big computer screen you could seen some very small dust specs and a minor blemish that I could barely see in person.
I am just a goof around / hobby picture taker (not a real photographer ) but I watch youtube videos by people who do it for a living. They spend a lot of time with editing software vs I spend nearly zero. ( just some minor cropping and compression to post them ).
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There are a lot of grit levels of bead / sand blasting that can be used. It is easy to get carried away and use too aggressive of approach.
Some people use tumbling to clean / polish out stones, reloading brass and aluminum parts.
It is common to put tape over threads and critical areas to protect them from the surface re-shaping.
It isn't terribly difficult to set up a home type II anodizing setup. This will create a moderately durable surface that can be dyed. It is surprisingly sensitive to small details about the aluminum, surface treatment and skin oils in terms of consistency / blotchy results.
Type III hard anodizing is more complex to set up and definitely requires some practice. It involves cold H2SO4 baths and all that goes along with running electricity through them.
There are companies that offer this as a service - but you have to be willing to pay the minimum fee.
Getting things to look nice is the hardest part of any project / material for me. Even for wood finishes I am finding that the detailed instructions seem to be written to meet a code compliance as opposed to actually the best results.
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It might make sense to pick up a couple of broken / not very functional lights and experiment with finishing so that you get the results that you like.